1. Technical Field
The present invention relates to a wavelength conversion element, a light source device, and a projector.
2. Related Art
In recent years, there exists a light source device having a solid-state light source such as a semiconductor laser, and a wavelength conversion element provided with a phosphor layer combined with each other. In such a light source device, the fluorescence conversion efficiency decreases as the temperature of the phosphor layer rises. For example, in the light source device disclosed in JP-A-2011-129354, the cooling efficiency of the phosphor is improved by bonding the phosphor layer to a heat radiation substrate with a metal bonding material.
However, in the light source device described above, since the expansion coefficient is different between the phosphor layer and the heat radiation substrate, there is a possibility that the phosphor layer is damaged or separated from the substrate due to the thermal stress caused when the phosphor layer generates heat.